In many situations, it is necessary to secure a line under tension. Often it is desirable to be able to quickly release the line from its secured position. In a number of applications, it is also important that the line be released automatically upon the tension in the line exceeding a predetermined amount. This tension could be one slightly less than the breaking point of the line, to prevent the line from being ruptured by the tension, or it could be some lesser amount determined by the use to which the line is put. For example, many line clamps or cleats are employed about a sail boat. As the sailing forces increase, the tension in secured lines also increases, it being necessary from time to time to adjust that tension by releasing and resecuring the line. Should such sailing forces increase suddenly, or should the line not be adjusted periodically to optimize sailing conditions, the tension on the line may increase to a point at which either the boat is in danger of capsizing or the line is in danger of breaking. Obviously, in either situation it is quite desirable to employ a clamp for the line that automatically releases it when such a limit condition is approached. This clamp should hold the line securely until the limit condition is reached, then release the line completely.
There are a few cleats or clamps that permit a line to be quickly secured. One typical design wedges the line between two jaws which include teeth forcing the line more deeply into the bite between the jaws. The line may be yanked free by pulling it away from the jaws, this action tending to fray the line. There are a few versions of such clamps or cleats that release the line should its tension exceed a predetermined limit, one design even permitting this release tension to be adjusted by the user. Such designs often challenge the strengths of the material employed in their construction. Often they are bulky and complex as well. In addition, some do not hold the line securely, but permit it to give somewhat with increasing tension, a very undesirable feature for some applications.